[furyg3]

For a second I thought you were one of my roommates, because we had a very similar setup for our (free) hot tub. Ours was a few years earlier and using older hardware.

We had an actual server in the garage, with a X10 firecracker on one serial port and a temperature sensor on the other. We used a 220V relay with a 110V pull, hooked up to a normal X10 switch controller. So from an X10 remote in the house, or via an sms gateway, we could turn on our hot tub remotely.

This had a few advantages including: 1) this setup was more accurate than the ancient thermal sensor/control on the hot tub 2) we never again had a large electric bill because someone forgot to turn it off and 3) really nice for when a date is going well and you can turn on the hot tub ahead of time :)